Does anybody know the source of this?

I put an imgur URL below, does anybody know who the artist of this is or what the source is? They're ad banners from the mobile version of rule34.xxx but it looks a lot like they used snippets from some hentai videos. I doubt anybody would go to that much trouble to make an animation like that just for a spam banner. They all look to be similar styles so I'm thinking they were done by the same artist originally. The one with the gangbang looks like it says something in behind the "free porn games" label, which is what makes me think they're sampled. It looks like it says "fan event."

imgur-com/a/k1hB8Th (replace dash with dot)